Conventionally, there are disclosed technologies to learn roads recognized by a user in order to optimize a guidance quantity for route guidance or Point of Interest (POI). For example, the technology described in Patent Literature 1 learns a road section the user actually traveled as the user-recognized road.
As another method of learning road sections, for example, the technology disclosed in Patent Literature 2 learns learning targets including not only a road the user actually traveled, but also a section unit (mesh area) including the road on the map.
However, the learning methods of the related art are unsatisfactory for the following reasons. The technology described in Patent Literature 1 learns only a traveled road section. Thus, a range of road learning becomes narrow because road sections other than the traveled road sections are not learned as the learning targets.
The technology described in Patent Literature 2 learns road sections included in the mesh area, which may include a road the user does not (or cannot) actually recognize.
The prior art indicates the widespread use of a navigation device that retrieves a route and provides guidance based on the route. Generally, such a navigation device includes a GPS receiver and displays the current location on the map.
The user may need information about an intersection in the vehicle's travel direction as well as facility information around the current location. However, the next intersection may not be displayed on the map depending on map scales.
According to the prior art, for example, Patent Literature 3 discloses the travel location display device that automatically changes map display scales and allows a single display window to display the current location and the next intersection in the vehicle's travel direction. This technology can provide a travel distance to the next intersection. Thus, the user can be free from psychological burden when he or she travels an unknown road using this kind of device.
However, in order to minimize the user's psychological burden while he or she travels an unknown road, it is insufficient to provide the information only about the next intersection.